1. Field of the Invention
The present invention relates to an oil supply apparatus of a linear compressor, and more particularly, to an oil supply apparatus of a linear compressor in which only one valve is used to suck and discharge oil, thereby reducing the number of parts and facilitating assembling of the valve.
2. Description of the Background Art
As is known, a linear compressor is an equipment for compressing a coolant by directly reciprocating a piston by means of a magnet and a coil instead of a crank shaft.
FIG. 1 shows a linear compressor in accordance with a conventional art. As shown in the drawing, the linear compressor includes a compression unit C installed in a horizontal direction inside a casing V filled with oil at its bottom, for sucking, compressing and discharging, and a oil feeder 0 fixedly combined at the outside of the compression unit C, to provide oil to each contact sliding portion (sliding portion) of elements.
As shown in FIG. 2, the oil feeder O includes a oil cylinder 21 attached onto the bottom surface of the compression unit C, a oil piston 22 inserted in the oil cylinder 21 and dividing the inner space of the oil cylinder into a suction space and a discharge space; a first and a second oil springs 23a and 23b positioned at both ends of the oil piston 22 to elastically support the oil piston 22; a oil suction valve 24 contacted to an oil outlet of the oil piston 22 and supported by the second oil spring 23b; and a oil discharge valve 25 installed at a oil outlet of the oil cylinder 21.
In detail, the oil suction valve 24 is inserted inside the oil cylinder 21, and compressively supported by the second oil spring 23b at the end portion of the oil outlet of the oil piston, so as to selectively open and close an oil flow path 22a of the oil piston 22.
The oil piston 22 is inserted in the oil cylinder 21 in a manner that its outer surface slidably contact the inner surface of the oil cylinder 21, in which the oil flow path 22a is formed in a lengthy direction to communicate the inlet and the outlet of the oil cylinder 21.
Reference numerals 1 denotes a frame, 1a denotes an oil inflow path, 1b denotes a first oil pocket, 1d denotes a oil circulation path, 1e denotes an oil discharge hole, 3 denotes a cylinder, 3a denotes an oil opening, 4 denotes an inside/outside lamination assembly, 5 denotes a magnet assembly, 6 denotes a piston, 7 denotes a suction valve, 9 denotes a suction pipe, 11 denotes a discharge cover, 12 denotes a discharge valve, 13 denotes a valve spring, 26 denotes a suction cover, 27 denotes a discharge cover, S1 denotes a suction space, and S2 denotes a discharge space.
Operation of the oil supply apparatus of the linear compressor constructed as described above in accordance with the conventional art will now be explained.
When the compression unit C is oscillated along with a magnetic assembly 5 in a horizontal direction by a linear reciprocal movement of the magnetic assembly 5, that is, an rotor of a linear motor, the oscillation is transferred to the oil cylinder 21 fixed at the compression unit C, so that the oil cylinder 21 is reciprocally moved.
In this respect, since the oil piston 22 is slidably inserted in the oil cylinder 21, oil is sucked and discharged by the inertial force resulted from the reciprocal movement of the oil cylinder 21.
That is, when the oil cylinder 21 is moved in the `P` direction as shown in FIG. 3A, the oil piston 22 overcomes the elasticity of the second oil spring 23b and is moved in the `Q` direction to thereby push the oil charged in the discharge space S2 in the `Q` direction, while oil flows in to be charged in the suction space S1 between the oil piston 22 and the oil suction cover 26.
At this time, the oil suction valve 24 is closed, closing the oil flow path 22a of the oil piston22, while the oil discharge valve 27 is pulled back in the `Q` direction to thereby open the discharge side of the oil cylinder 21.
Reversely, in case that the oil cylinder 21 is moved in the `Q` direction in FIG. 3B, the oil piston 22 overcomes the first oil spring 23a and is moved in the `P` direction, so that the pressure of the discharge space S2 becomes relatively low compared to that of the suction space S1 and the oil of the suction space S1 flows to the discharge space S2.
At this time, the oil suction valve 24 is turned to open in the `Q` direction, while the oil discharge valve 27 is turned in the `P` direction, closing the discharge side of the oil cylinder 21 to thereby prevent the oil from flowing backward.
However, as to the oil supply apparatus of the linear compressor of the conventional art, since the number of parts constructing the oil feeder is too many, the number of assembly process is increased, causing a problem in that its productivity is deteriorated.
In addition, since the oil suction valve controlling inputting and outputting of the oil is so small, its fabrication and assembling is very difficult.
Moreover, the opening and closing portion of the oil suction valve contacts the compressive coil spring supporting the oil piston, opening and closing operation of the oil valve is not made smoothly, failing to control properly the input and outputting of the oil.